Non-metallic cover for a fixture

ABSTRACT

An assembly includes a fixture including an opening shaped to receive a portion of a turbine engine component. A non-metallic cover is placed over at least a portion of the fixture. The cover facilitates reducing metal to metal contact of the fixture and the turbine engine component when the turbine engine component is installed in the fixture, and facilitates reducing scratching of the turbine engine component.

BACKGROUND OF THE INVENTION

This application relates to a non-metallic cover that is positioned on afixture that holds a turbine engine component during a manufacturingprocess, the cover protecting the turbine engine component fromscratches.

Gas turbine engines typically include turbine rotors having a pluralityof removable turbine blades and a plurality of static vanes. Before amanufacturing process, a metal turbine blade is installed in a metalfixture. The turbine blade must be accurately aligned with an opening inthe fixture to prevent scratching of the turbine blade duringinstallation. The metal to metal contact between the turbine blade andthe fixture can scratch the turbine blade. If the manufacturing processis a laser drilling process, laser splatter can collect on the fixture,which can be difficult to remove.

There is a need in the art for a cover that protects a turbine enginecomponent from scratches and that overcomes the other drawbacks andshortcomings of the prior art.

SUMMARY OF THE INVENTION

An assembly includes a fixture including an opening shaped to receive aportion of a turbine engine component. A non-metallic cover is placedover at least a portion of the fixture. The cover facilitates reducingmetal to metal contact of the fixture and the turbine engine componentduring installation of the turbine engine component in the fixture, andfacilitates reducing scratching of the turbine engine component.

The turbine engine component can be a turbine blade including a basewith a dovetail shape that defines a groove that extends along a lengthof base. The shape of the opening of the fixture generally correspondsto the shape of the base of the turbine blade. The fixture includesprojections on opposing sides of the opening, and the cover includesprojections on opposing sides of an opening of the cover. In oneexample, the projections of the cover taper inwardly. When the cover isplaced on the fixture, the projections of the cover generally align withthe projections of the fixture.

When the turbine blade is to be installed in the fixture, the base ofthe turbine blade is aligned with the opening of the fixture. Theturbine blade is then slid such that the projections of the cover arereceived in the grooves of the turbine blade to guide the turbine blade.As the turbine blade continues to move, the projections of the fixtureare received in the grooves of the base of the turbine blade and guidethe turbine blade until it is installed.

These and other features of the present invention can be best understoodfrom the following specification and drawings, the following of which isa brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a simplified cross-sectional view of a standard gasturbine engine;

FIG. 2 illustrates a turbine blade as is generally known in the priorart;

FIG. 3 illustrates a fixture that holds a turbine blade;

FIG. 4 illustrates a cover that is to be placed on the fixture;

FIG. 5 illustrates the cover positioned on the fixture;

FIG. 6 illustrates a perspective view of the cover positioned on thefixture; and

FIG. 7 illustrates the cover positioned on the fixture with the turbineblade installed in the fixture.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A gas turbine engine 10, such as a turbofan gas turbine engine,circumferentially disposed about an engine centerline (or axialcenterline axis 12) is schematically shown in FIG. 1. The gas turbineengine 10 includes a fan 14, compressors 16 and 17, a combustion section18 and turbines 20 and 21. This application extends to engines without afan, and with more or fewer sections. As is well known in the art, airis compressed in the compressors 16 and 17, mixed with fuel and burnedin the combustion section 18, and expanded in turbines 20 and 21. Theturbines 20 and 21 include rotors 22 which rotate in response to theexpansion, driving the compressors 16 and 17 and the fan 14. Theturbines 20 and 21 include alternating rows of rotating airfoils orturbine blades 24 and static airfoils or vanes 26. In FIG. 1, theturbine blades 24 are removable from the rotors 22. It should beunderstood that this schematic view is included simply to provide abasic understanding of the sections in the gas turbine engine 10 and isnot limiting. The exemplary assemblies, covers and methods describedherein apply to all types of gas turbine engines for all types ofapplications.

FIG. 2 shows a known turbine blade 24. A platform 42 is provided at aradially inner portion of the turbine blade 24, while an airfoil 40extends radially (as seen from the axial centerline axis 12) outwardfrom the platform 42. A base 44, located under the platform 42, has adovetail shape including a hill 46 and a valley 50. In one example,there are two hills 46 and 48, and the valley 50 is located between thetwo hills 46 and 48. The valley 50 defines a groove 52 that extendsalong a length 54 of the base 44 of the turbine blade 24. The valley 50has a width 56, and the hills 46 and 48 have a width 58. It should beappreciated to a person of ordinary skill in the art that the base 44may include various configurations.

Before a manufacturing process, the turbine blade 24 may be installed ina fixture 60 that holds the turbine blade 24 during the manufacturingprocess. In one example, the manufacturing process can be a laser holedrilling process. In one example, the fixture 60 is a serration fixture.In one example, the fixture 60 is made of metal.

As shown in FIG. 3, the fixture 60 includes an opening 62 having a shapethat generally corresponds to the shape of the base 44 of the turbineblade 24. The fixture 60 includes an elongated projection 64. In oneexample, the fixture 60 includes two projections 64, and one of theprojections 64 is located on each side of the opening 62. A distance 66is defined between the projections 64. The fixture 60 also includes astop 68 and an alignment feature 70. In one example, the alignmentfeature 70 is a circular head. In another example, the fixture 60includes two alignment features 70.

As shown in FIG. 4, a non-metallic cover 72 is placed over at least aportion of the fixture 60. In one example, the cover 72 is placed over afront portion of the fixture 60. In one example, the cover 72 is made ofglass filled nylon. The cover 72 includes an opening 74 and an elongatedprojection 76. In one example, the cover 72 includes two projections 76that taper inwardly towards a longitudinal axis A of the opening 74 asthe projections 76 extend from a front side 84 to a rear side 86 of thecover 72, and one of the projections 76 is located on each side of theopening 74. A distance 88 between the projections 76 is located near thefront side 84 of the cover 72 and is greater than a distance 90 betweenthe projections 76 located near the rear side 86 of the cover 72. Thatis, the distance between the projections 76 is not constant. A flattenedportion 92 is located under each of the projections 76, and each of theflattened portions 92 also taper inwardly towards the rear side 86 ofthe cover 72. The cover 72 also includes an alignment feature 94. In oneexample, the alignment feature 94 is a hole. In another example, thecover 72 includes two alignment features 94.

The cover 72 is produced using “Rapid Prototyping,” eliminating the needof complicated machining. For example, the cover 72 can be made directlyfrom a computer (CAD) model.

As shown in FIGS. 5 and 6, when the cover 72 is placed on the frontportion of the fixture 60, the alignment features 70 of the fixture 60are aligned with the alignment features 94 of the cover 72, aligning thecover 72 relative to the fixture 60. In one example, the alignmentfeatures 70 of the fixture 60 are received in the alignment features 94of the cover 72. Each projection 76 of the cover 72 generally alignswith one of the projections 64 of the fixture 60. That is, the distance90 between the projections 76 of the cover 72 is generally equal to thedistance 66 between the projections 64 of the fixture 60 at the locationwhere these components meet. The opening 62 of the fixture 60 is exposedand not covered by the cover 72. That is, the opening 74 of the cover 72does not block access to the opening 62 of the fixture 60.

FIG. 7 shows an assembly of the base 44 of the turbine blade 24installed in the fixture 60. When the turbine blade 24 is to beinstalled in the fixture 60 before a manufacturing process, the base 44of the turbine blade 24 is aligned with the opening 62 of the fixture60. The turbine blade 24 is then slid in a rearwardly direction, and theprojections 76 of the cover 72 are received in the grooves 52 of theturbine blade 24. The distance 88 of the opening 74 of the cover 72 isgreater than the width 56 of the base 44 of the turbine blade 24,minimizing contact between the base 44 and the cover 72 and helping tolocate the turbine blade 24 in the fixture 60.

The turbine blade 24 is installed from the front portion of the fixture60. As the turbine blade 24 is slid rearwardly, a distance between theopening 74 of the cover 72 and the base 44 decreases as the projections76 taper inwardly. As the turbine blade 24 continues to move rearwardly,the projections 64 of the fixture 60 are received in the grooves 52 ofthe base 44 of the turbine blade 24. As the distances 66 and 90 aregenerally equal, the turbine blade 24 smoothly transitions from movingrelative to the cover 72 to moving relative to the fixture 60. The stop68 of the fixture 60 prevents further rearward movement of the turbineblade 24 relative to the fixture 60.

In the above-described example, the fixture 60 and the cover 72 includeprojections 64 and 76, respectively, that engage grooves 52 of a turbineblade 24. However, the fixture 60 and the cover 72 can include groovesthat receive a projection of the turbine blade 24 (formed by one of thehills 46 and 48 as it extends along the length 54 of the base 44 of theturbine blade 24). Alternately, the alignment feature 70 of the fixture60 can be a hole, and the alignment feature 94 of the cover 72 can be acircular head or any type of alignment feature.

The cover 72 is made of a non-metallic material and facilitates reducingthe turbine blade 24 from being scratched or damaged as the turbineblade 24 is installed in the fixture 60. The cover 72 facilitatesreducing metal to metal contact between the turbine blade 24 and thefixture 60 that might nick, dent or scratch the turbine blade 24 as theturbine blade 24 is installed in the fixture 60. Because the distance 88of the opening 74 of the cover 72 is greater than the width 56 of thebase 44 of the turbine blade 24, the base 44 is easily inserted into theopening 74 of the cover 72.

After the turbine blade 24 is installed, a manufacturing process isperformed. For example, when the manufacturing process is a laserdrilling process, the assembly is mounted in a laser machine and theturbine blade 24 is drilled with a drilling machine. During the laserdrilling process, laser spatter can form. If the laser spatteraccumulates on the cover 72 of the fixture 60, the laser splatter caneasily be removed from the non-metallic cover 72. In the event that thecover 72 becomes covered with laser splatter, the cover 72 can be easilyreplaced with a new cover 72.

The foregoing description is only exemplary of the principles of theinvention. Many modifications and variations are possible in light ofthe above teachings. It is, therefore, to be understood that within thescope of the appended claims, the invention may be practiced otherwisethan using the example embodiments which have been specificallydescribed. For that reason the following claims should be studied todetermine the true scope and content of this invention.

What is claimed is:
 1. An assembly used in performing a manufacturingprocess on a turbine engine component, the assembly comprising: afixture including a fixture opening shaped to receive a portion of aturbine engine component; and a non-metallic cover positioned over atleast a portion of an external surface of the fixture, wherein thenon-metallic cover is visible when positioned over the at least aportion of the external surface of the fixture; wherein the fixture hasa top surface, a front surface, and a side surface, and the non-metalliccover has a top surface, a front surface, and a side surface, and thetop surface, the front surface, and the side surface of the non-metalliccover are positioned over the top surface, the front surface, and theside surface of the fixture, respectively.
 2. The assembly as recited inclaim 1 wherein the fixture is metal and the non-metallic cover is madeof glass filled nylon.
 3. The assembly as recited in claim 1 wherein thefixture includes a fixture alignment feature and the non-metallic coverincludes a cover alignment feature, and the fixture alignment featureand the cover alignment feature position the non-metallic cover relativeto the fixture.
 4. The assembly as recited in claim 1 wherein theturbine engine component is a turbine blade.
 5. The assembly as recitedin claim 1 wherein the turbine engine component includes a base, and thebase has a shape corresponding to a shape of the fixture opening.
 6. Theassembly as recited in claim 1 wherein the fixture includes a fixtureprojection in the fixture opening and the non-metallic cover includes acover projection that substantially aligns with the fixture projectionwhen the non-metallic cover is installed on the fixture.
 7. The assemblyas recited in claim 6 wherein the non-metallic cover is positioned overa front portion of the fixture, and the turbine engine component isinstalled in the fixture from the front portion such that the turbineengine component is first guided by the cover projection and is thenguided by the fixture projection.
 8. The assembly as recited in claim 6wherein turbine engine component includes a base having a groove, andthe cover projection is received in the groove as the turbine enginecomponent is installed in the fixture to guide the turbine enginecomponent relative to the cover.
 9. The assembly as recited in claim 6wherein turbine engine component includes a base having a groove, andthe fixture projection is received in the groove as the turbine enginecomponent is installed in the fixture to guide the turbine enginecomponent relative to the fixture.
 10. The assembly as recited in claim6 wherein the fixture projection comprises two fixture projections andthe cover projection comprises two inwardly tapering cover projections,wherein each of the two fixture projections substantially align with oneof the two inwardly tapering cover projections.
 11. A cover to protect aturbine engine component installed in a fixture during a manufacturingprocess performed on the turbine engine component, the cover comprising:a non-metallic body positioned over at least a portion of an externalsurface of a fixture, wherein a turbine engine component is installablein the fixture, and the non-metallic body is visible when positionedover the at least a portion of the external surface of the fixture;wherein the fixture has a top surface, a front surface, and a sidesurface, and the non-metallic cover has a top surface, a front surface,and a side surface, and the top surface, the front surface, and the sidesurface of the non-metallic cover are positioned over the top surface,the front surface, and the side surface of the fixture, respectively.12. The cover as recited in claim 11 wherein the non-metallic body ismade of glass filled nylon.
 13. The cover as recited in claim 11including a cover projection that guides the turbine engine componentduring installation of the turbine engine component in the fixture. 14.The cover as recited in claim 13 wherein the cover projection comprisestwo inwardly tapering cover projections.
 15. The cover as recited inclaim 11 including an alignment feature that aligns the cover relativeto the fixture.
 16. A method of performing a manufacturing process on aturbine engine component, the method comprising the steps of:positioning a non-metallic cover over at least a portion of an externalsurface of a fixture, wherein the non-metallic cover is visible whenpositioned over the at least a portion of the external surface of thefixture; and installing a turbine engine component in a fixture openingof the fixture; wherein the step of positioning the non-metallic coverover the at least a portion of the external surface of the fixtureincludes positioning the non-metallic cover relative to the fixture suchthat a top surface, a front surface, and a side surface of thenon-metallic cover is positioned over a top surface, a front surface,and a side surface of the fixture, respectively.
 17. The method asrecited in claim 16 further including the step of performing amanufacturing process on the turbine engine component after the steps ofpositioning the non-metallic cover over the at least a portion of theexternal surface of the fixture and installing the turbine enginecomponent in the fixture opening of the fixture.
 18. The method asrecited in claim 17 wherein the step of performing the manufacturingprocess includes laser drilling the turbine engine component.
 19. Themethod as recited in claim 16 wherein the step of installing the turbineengine component includes the step of sliding the turbine enginecomponent relative to the fixture, wherein the non-metallic cover firstguides the turbine engine component and the fixture then guides theturbine engine component.
 20. The assembly as recited in claim 3 whereinthe fixture alignment feature is a circular head and the cover alignmentfeature is a hole that receives the circular head, and the circular headis visible when the non-metallic cover is positioned over the at least aportion of the external surface of the fixture.
 21. The assembly asrecited in claim 4 wherein the fixture is not a turbine rotor.
 22. Theassembly as recited in claim 4 wherein the turbine blade is received inthe fixture opening of the fixture for manufacturing procedures prior tobeing received in a slot in a turbine rotor.
 23. The method as recitedin claim 16 including the step of aligning the non-metallic cover withthe fixture by locating an alignment feature of the fixture in a hole ofthe non-metallic cover, and the alignment feature is visible when thenon-metallic cover is positioned over the fixture.
 24. The method asrecited in claim 17 including the steps of removing the turbine enginecomponent from the fixture opening of the fixture after the step ofperforming the manufacturing process on the turbine engine component andinstalling the turbine engine component in a slot in a turbine rotor.25. The method as recited in claim 24 wherein the turbine enginecomponent is a turbine blade.